Quote: “There’s no vaccine against what threatens us as a community. Every generation needs to be taught anew.”

Morris Casuto is talking about his life’s work, the fight against hate and prejudice, and how it gets depressing sometimes because those are weeds that never stop sprouting.

“But that doesn’t mean we stop pushing,” he said, his cadence sermon-like. “Pushing to be not only who we want to be, but who we can be.”

Then he cocks his head to one side and asks, “Did you hear that? ‘The Battle Hymn of the Republic’ was playing in the background.”

Classic Casuto: climbing up on his high horse and then knocking himself off it, usually with a joke. Taking his work seriously, but not himself. Laughing to mask the pain.

For 37 years he’s been San Diego’s go-to person on bigotry, a chronicler of neo-Nazis, a condemner of extremists, a trainer of hate-crimes investigators.

That’s made the regional director of the Anti-Defamation League a regular presence in the media — and the target of bomb threats and painted swastikas. He’s worn a bulletproof vest, had to learn to work and live behind always-locked doors. The police from time to time have parked in front of his University City home.

“It’s been an interesting life,” he said.

Been, past tense. What the racists could never make him do he’s doing himself: stepping down from his post, at the end of the month.

“It’s time to give someone else the opportunity to dream,” he said, “because that’s what this job is, dreaming that the community can be a safer, better place in part because of your efforts.”

Wait for it — nothing. No joke at his own expense this time. He means that stuff about making the community a better place, a more understanding place. Always has.

It’s why he’s attended Ku Klux Klan rallies. It’s why, even though he’s Jewish, he met with the pope and loves Christmas music. It’s why he studies military history even as he promotes peace.

It’s what’s kept him going for almost four decades.

OK, now he tells a joke.

A guy who’s facing execution makes a bargain with the king: Let me live another year and I’ll teach your horse to talk.

The other inmates scoff at him, but he reasons that a lot could change in a year. The horse could die. The king could die. He could die. “And who knows? I could teach that horse to talk.”

Casuto’s eyes dance behind his glasses. “I like to think that’s the kind of optimist I am,” he said.